The polyphenylene ether resins constitute a family of high performance engineering thermoplastics possessing outstanding properties which makes them useful and desirable for many applications. These materials and methods for their preparation are described in many publications, including U.S. Pat. Nos. 3,306,874 and 3,306,875 to Allan Hay, and U.S. Pat. Nos. 3,257,357 and 3,257,358 to Gelu Stamatoff.
The polyphenylene ether resins are admixable with rubber modified high impact polystyrene to form blends which can be molded into articles having improved impact strength.
It is known that additional properties of polyphenylene ether resins and blends can be materially upgraded by blending them with certain other polymeric materials. Polyphenylene ether resins alone, when molded, are somewhat brittle and may shatter or fracture upon impact. Also, the relatively high melt viscosity and softening point of the polymer can cause difficulty in processing.
It has been found that polyolefin resins, such as low density polyethylene, can be incorporated in polyphenylene ether resin blends to lower the melt viscosity of the polyphenylene ether and to improve the melt flow. Compositions of this type are disclosed by Lee, Jr. in U.S. Pat. No. 4,166,055. This same additive, in relatively small amounts, is also known to function as an impact modifier, external lubricant and mold release agent for the blends.